Ratio Calculator
Simplify a:b and solve a proportion.
Ctrl+Enter runs. Ctrl+Shift+Backspace clears.
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Leave one part of a:b = c:d empty. The missing integer is solved exactly, or you get a clear message when the result is not an integer.
About this tool
Simplify a ratio like 12:18 to 2:3, or solve a proportion such as 3:4 = x:20. Leave the unknown part empty and the tool finds it exactly.
How to use it
- 01
Enter the known parts A, B, C and D of a:b = c:d.
- 02
Leave the unknown part empty.
- 03
Read the missing value or the simplified ratio.
Frequently asked questions
How do I solve a proportion?
Fill in three of the four values and leave one field empty. The missing value is calculated from a × d = b × c.
What if the answer is not a whole number?
The tool tells you clearly that the proportion has no integer solution instead of rounding.